Steel and its manufacture



J. R. C. MARSH STEEL AND ITS'MANUFACTURE Sept. 18, 192 8. 1,684,841

Filed Jan. 19. 1922 Ill Patented Sept. 18, 1928.

UNITED STATES PATENT OFFICE.

JOSEPH RUSSELL CORNELL MARSH, OF ARLINGTON HEIGHTS, ILLINOIS, ASSIGNORTO FRANCIS NORWOOD BARB, OF CHICAGO, ILLINOIS.

STEEL AND ITS MANUFACTURE.

7 Application filed January 19, 1922. Serial No. 530,261.

My present invention relates broadly to the introduction of modifyingelements into metals, and more particularly to increasing the carboncontent of metals 'such as iron and steel, and includes'the introductioninto the metal of a carboniferous material in such a form that it willreadily combine with the metal with the introduction of the minimum ofobjectionable material into the resultant product and with theminimization of presence'of any objectionable characteristics, andfurther includes the introduction of this carboniferous material in amanner that will give the most oflicient results with the leastdeleterious incidents, with the greatest facllity and accuracy.

Among the principal objects of the present invention are the productionof a metal having a modifying element introduced therein, such forexample as steel having a predetermined carbon content, accuratelyproduced and reproduced on a commercial scale, a process for introducingthe modifiying element i such as carbon during the course of productionin such a manner as to gain closely predetermined results, and animproved resultant product, such as steel being within closelypredetermined limits and free from objectiona le characteristics.

In the accompanying drawing I havethus treated the manner in which themolten metal entrains the flakedparticles of carbon preferably employedby me.

In the aforesaid drawing which I have provided for the tain steps in thecarrymg out of my improved method of introducing a modifying elementinto a metal in the manufacture, for example, of steel having apredetermined carbon content- I v Figure l is a sectional viewof a massof flake graphite disposed in a ladle;

' Figure 2 is a sectional View illustrative of the position the contentsof the ladle assumes as the streamof molten metal is introducedthereinto; and

Figures 3 and 4 are views similar to those of Figures 1 and 2illustrative of prior art to an extent desirable for the proper andadequate understanding of my present invention;

As willbe understood on viewing Figures 1 and 2 of the vdrawing, thebottom of' the ladle is indicated at 10, thev mass of flake graphite at11, the descending stream of mol characterized by purpose ofillustrating certen metal from the and the mass 13 It will be observedon inspection of Figure 1 that the flakes of graphlte lie flat in theladle and being thin consequently quickly attain the proper temperaturewhen the ladle is properly heated.

As the stream of molten metal strikes the flakes of graphite broadside,it turns and entrains them and carries them edgewise downwardly andlaterally, and inasmuch as the graphite thus entrained consists, asnoted, of very thin flakes, of great superficial area which may quicklyand thoroughly absorb heat, they will be readily taken up by andcombined with the molten metal and thoroughly disseminated throughoutthe mass thereof owing to the gyratory motion imparted thereto throughthe action of the stream 12, and thus a homogeneous product is attained.

That part of the molten mass which is out of the path of the stream 12floats upon and rises with the top of the rising mass of molten metalcontained within the ladle, 10, but is drawn into the mass as the streamof molten metal 12 continues to run into the ladle 11.

On comparing the illustration of Figures 1 and 2 with those of Figures 3and 4, it will be observed that when carbon in such forms as groundanthracite coal, coke breeze and the like, which is illustrated at 11,is employed, a much greater quantity is necessary in order to have thesupply of carbon of the same initial quantity as that indicated at 11.

It will be appreciated also that owing to the relatively impure form ofsuch organic forms of carbon, the volatile matter may be as much as 60%as against 2% in the case of flake graphite. It will readily bediscerned that owing to the relative thickness of the particles of suchorganic forms of carbon not only is a much longer time required forheating them, with consequent oxidization, but also when such organicforms are forced into the mass of molten metal, the volatile matter isentrained and atmospheric air is carried along in such a way as toproduce large and most undesirable quantities of hurtgases such as C0,C0,, H 00 and the 1 e.

In the practice of my present invention I have found it desirable orpurposes of introducing carbon into metal such as in the manufacture ofsteel forthe purpose of producing a definite carbon content combinedtherewith, to employ highly comminuted graphite preferably in the formof flakie graphite. Such graphite is generally commercially pure inrespect to sul hur, phosphorus, carborundum and the ike, and isotherwise free from any detrimental content.

In the utilization of flake graphite to be introduced into the metal, asabove suggested, I have found it desirable first to introduce into theladle or other container to be used a predetermined quantity of theflake raphite which is heated and maintained in aheated state in theladle, preferably by preheating the ladle at least to a red temperature.

The molten metal, such as steel from the furnace, is then introducedinto the ladle onto the to of the heated graphite, the temperature o themass being that required for makso practiced ing steel and thetemperature of the gra hite being such that on one hand there will noappreciable chilling action on the metal and on the other hand allvolatile or combustible matter will be ex elled.

The flake grap ite being lighter molten metal, and the flakes lying insubstantially a horizontal plane, the mass thereof floats as a stratumat the top of the molten content of the ladle, thus forming a protectivecoating to the metal and preventing oxidization thereof, and asadditional molten metal in entering the ladle passes through thisstratum it not only takes up in chemical combination a portion of thecarboniferous material but also initiates a quasi-circulatory movementof a physically entrained portion through the mass, thus in factbringing the carbon and the molten metal into intimate contact in theform of a physical mixture, and so facilitatin still further combinationbetween the car n and the molten metal, and the process may be carriedon even to the point of saturation.

As a result of the use of flake graphite as a carbonaceous material twoimportant conseguences are effected which are broadly that:

rst, the desired chemical combination between the carbon and metal iseffected to a high degree; and, second, the process maybe than the bonmay be taken into the chemical combination and thepresence of free oruncombined carbon may be avoided.

By the foregoing practice the maximum contact between the particles ofcarbon and of molten metal is established, and as a result the maximumof chemical combination between the two is efiected. I

Aaa consequence the exact amount of carbon that will chemically combinewith a predetermined amount of molten metal can be that substantiallyall of the caremploy carbon not in chemical combination,

such so-called grapliitic carbon will be uniformly distributed throughthe mass, and consequently the amount of carbon necessary to result in apredetermined proportion of graphitic carbon throu hout the mass canalso be accurately gauge in advance by the employment of myimprovedprocess.

By the use of carbon in'the form of flake graphite in the processdescribed, I am enabled to obtain not only a steel having an increase ofcarbon content rise chemically combined of .047% but, with the sameproportions between the carboniferous material and the molten mass, thedesired results may be Quickly, uniformly, and consistently pro-.

need.

I have thus found in actual practice that the addition of each ounce ofgraphite (conof 85% ake graphite according to the process hereinaboveset forth; Analysis of tie carbon steel so produced showed all combinedcarbon and no gra hitic carbon whatsoever.

Those who are skilled in the art will appre ciate that not only am Iable to produce for example a steel havin a maximum carbon content, butalso one t at is simultaneously of extraordinary purity and of maximumdensity and homo'eneity throughout owing to the ex ulsion o forei andvolatile matters and e prevention 0 the occlusion of entrainedimpurities and gases giving rise to hard spots, pockets and otherimperfections.

Owing to the flatness and thinness characteristic of carbon particlespresented in the form of the flake graphite preferably emplo ed by me,these particles not only tend to cat on the mass of molten metal in aposii tion best adapted to be entrained by an impinging mass of moltenmetal but are obviously of a form most particularly adapted forinstantaneous heatin and as a consequence combine most quic ly with themetal into contact with which they are brought as will be readilycomprehended on consideration of the accompanying drawing.

a mechanical mixture of another portion of the carbon to form graphiticcarbon.

it will thus be discerned that l am enabled.

to produce modified ferrous materials wherein. the quantity content ofthe modifying element, such as carbon, and also the nature thereof maybe regulated with great nicety and precision.

it will furthermore be manifest that because of the freedom fromvolatile matter, sulphur, phosphorus, carborundum and other undesirableelements graphite in the form and condition employed by me, and the factthat such material does not tend to entrain atmospheric air or othergases, the practice of my improved process tends neither to producecarborundum or other hard spots nor increase the amount of occludedgases in, nor the sulphur and phosphorus content of the steel therebyproduced but rather to produce and enable the reproduction of a steelcharacterized as being Within closely predetermined iimitaandconsequently one not only free from objectionable characteristics butalso one answering the desired specifications.

Having thus described my invention and illustrated use, What I claim asnew and desire to secure by Letters Patent is 1. In the process ofmaking steel, the steps which include adding stream of moulten metal toloose 'graphitie material in flake form and in a state or subdivision tobe highly mobile whereby the stream of moulten metal will form anintermixed current or" graphitic material and metal to rapidly andcompletely carburize the metal.

2. In the process of making steel, the steps which include adding astream of moulten metal to loose graphitic material in flake form, inheated condition short of i a state of subdivision to be ighly mobilewhereby the stream of moulten metal will form an intermixed current ofgraphitic ma terial and metal to rapidly and completely carburize themetal.

3. In the process which include adding a stream of moulten metal toloose graphitic material in flake form and in a state of subdivision tobe highly mobile and circulating the incoming stream or" metal incontact with the graphitic material to have substantial portions thereofform a sealing layer for the metal and continuing the circulationwhereby the stream of moulten metal will form an intermixed current ofgraphitic material and metal to rapidly and completely carburize themetal.

a. In the process of making steel, the steps which include adding astream of moulten metal to loose, unconfined graphite in flake form andcirculating the metal relatively to the graphite material to formintermixed currents of metal and graphite.

5. lln the process of making steel, the steps nition and in of makingsteel, the steps i Which include impinging a stream of moulten metalthrough a bed of unconfined flake graphite in loose form and in a stateof subdivision to be highly mobile, and circulating the metal and rentsWhile substantially maintaining the moulten metal coated with a layer ofgraphite.

6. In the process of making steel, the steps which include impinging astream of moulten metal against preheated flake graphite in a state ofsubdivision to be mobile and freely and completely circulate With thestream of metal and form intermixed substantially uniform currentsthereof. V

In testimony whereof I have hereunto signed my name.

JOSEPH RUSSELL (Clllllillill. MARSH.

graphite in intermixed cur--

